//条件语句
if (0 > 1) {
    if条件语句成立
}

var i = 3

//条件语句
//循环语句
var arr = [1, 2, 3, 4, 5]

for (var i = 0; i < arr.length; i++) {//i=i+1
    arr[i] = arr[i] * 10
}

console.log(arr);